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Digit Sum Magic Worksheet

Maths tricks trick 10: Digit-sum magic · Set 58 · 40 questions
TalentJR

The trick (Digits add to the 9 table): Add the digits you can see. Find the next number in the 9 table (9, 18, 27 …) above that total. The hidden digit is the difference. (Any number minus its digit sum is in the 9 table too.)

NameDateTime takenScore ___ / 40
  1. 1.Take 76 and take away the sum of its digits. What do you get?
  2. 2.Take 47 and take away the sum of its digits. What do you get?
  3. 3.?631 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  4. 4.?448 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  5. 5.Take 44 and take away the sum of its digits. What do you get?
  6. 6.?319 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  7. 7.?463 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  8. 8.190? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  9. 9.Take 27 and take away the sum of its digits. What do you get?
  10. 10.87?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  11. 11.?213 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  12. 12.23?1 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  13. 13.79?6 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  14. 14.25? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  15. 15.?968 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  16. 16.Take 51 and take away the sum of its digits. What do you get?
  17. 17.Take 71 and take away the sum of its digits. What do you get?
  18. 18.?383 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  19. 19.Take 26 and take away the sum of its digits. What do you get?
  20. 20.732? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  21. 21.?820 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  22. 22.1?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  23. 23.?226 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  24. 24.888? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  25. 25.Take 84 and take away the sum of its digits. What do you get?
  26. 26.Take 56 and take away the sum of its digits. What do you get?
  27. 27.?206 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  28. 28.Take 43 and take away the sum of its digits. What do you get?
  29. 29.Take 50 and take away the sum of its digits. What do you get?
  30. 30.Take 82 and take away the sum of its digits. What do you get?
  31. 31.88?9 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  32. 32.?444 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  33. 33.46?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  34. 34.?341 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  35. 35.6?4 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  36. 36.24?2 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  37. 37.?687 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  38. 38.Take 11 and take away the sum of its digits. What do you get?
  39. 39.?154 is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?
  40. 40.15? is in the 9 times table. One digit is hidden, and it is not 0. What is the hidden digit?

Answer key

  1. 63
  2. 36
  3. 8
  4. 2
  5. 36
  6. 5
  7. 5
  8. 8
  9. 18
  10. 3
  11. 3
  12. 3
  13. 5
  14. 2
  15. 4
  16. 45
  17. 63
  18. 4
  19. 18
  20. 6
  21. 8
  22. 8
  23. 8
  24. 3
  25. 72
  26. 45
  27. 1
  28. 36
  29. 45
  30. 72
  31. 2
  32. 6
  33. 6
  34. 1
  35. 8
  36. 1
  37. 6
  38. 9
  39. 8
  40. 3

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